CN112276873B - Workbench and method for detecting workpiece position deviation and alignment by using sensor - Google Patents

Workbench and method for detecting workpiece position deviation and alignment by using sensor Download PDF

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Publication number
CN112276873B
CN112276873B CN202011037845.XA CN202011037845A CN112276873B CN 112276873 B CN112276873 B CN 112276873B CN 202011037845 A CN202011037845 A CN 202011037845A CN 112276873 B CN112276873 B CN 112276873B
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workpiece
axis
point
numerical control
linear motion
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CN112276873A (en
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吕浩
程教杨
周炳水
来文江
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China United Engineering Corp Ltd
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China United Engineering Corp Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25H—WORKSHOP EQUIPMENT, e.g. FOR MARKING-OUT WORK; STORAGE MEANS FOR WORKSHOPS
    • B25H1/00—Work benches; Portable stands or supports for positioning portable tools or work to be operated on thereby
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P90/00—Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
    • Y02P90/02—Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Automatic Control Of Machine Tools (AREA)

Abstract

The invention provides a workbench and a method for detecting the position deviation and alignment of a workpiece by using a sensor, which have the advantages of simple equipment structure, low cost and high efficiency. The numerical control longitudinal linear motion unit is fixedly arranged on the machine base; the numerical control transverse linear motion unit is arranged on the numerical control longitudinal linear motion unit, and the movement directions of the numerical control longitudinal linear motion unit and the numerical control transverse linear motion unit are mutually perpendicular; the workpiece supporting disc is arranged on the numerical control transverse linear motion unit; the sensor is arranged on the sensor bracket; the sensing points of the two sensors are all positioned on the central axis of the numerical control longitudinal linear motion unit and are arranged front and back. The method comprises the steps of detecting and aligning the position deviation of the workpiece with the detected edge being a straight line, detecting and aligning the position deviation of the workpiece with the detected edge being a circular arc or a round shape, and detecting and aligning the position deviation of the workpiece with the detected edge being an oval shape.

Description

Workbench and method for detecting workpiece position deviation and alignment by using sensor
Technical Field
The invention relates to a workbench and a method for detecting workpiece position deviation and alignment by using a sensor.
Background
For various automatic production equipment and automatic production lines, the starting end of the process flow is workpiece loading, and when the workpiece is loaded, the workpiece is required to be accurately positioned so as to realize the subsequent automatic process flow. The flexible workpiece or the sheet workpiece and some other types of workpieces are difficult to accurately position by mechanical limiting modes such as a clamp, a guide piece, a rigid stop block and the like, so that the workpiece is inevitably subjected to position deviation after being mounted, and the workpiece must be aligned.
In the prior art, a visual recognition system is mostly adopted, and the workpiece is aligned by comparing the difference between the actual position and the ideal position of the workpiece. While the problem of workpiece position detection is solved, there are several other problems: first, the visual recognition system is expensive, resulting in high equipment costs; secondly, the recognition success rate of the visual recognition system is greatly influenced by the product and the surrounding environment, and one workpiece is often required to be compared for a plurality of times, so that the normal operation and the production efficiency of the equipment are directly influenced. Thirdly, for large-scale workpieces and strip-shaped workpieces, the visual recognition system needs a plurality of cameras to splice, so that the recognition success rate is reduced, and meanwhile, the equipment cost is increased.
In the prior art, workpiece alignment is realized by installing a plurality of photoelectric sensors on a robot. While replacing visual recognition systems with photosensors partially reduces equipment costs, there are also some other problems: firstly, only the alignment of a workpiece with a rectangular and square outline shape can be realized; second, robots are expensive, resulting in higher equipment costs; third, the robot control system is complex.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides the workbench and the method for detecting the position deviation and the alignment of the workpiece by using the sensor, which have reasonable structural design, simple equipment structure, low cost and high efficiency.
The invention solves the problems by adopting the following technical scheme: a workbench for detecting workpiece position deviation and alignment by using a sensor, which is characterized in that: the device comprises a sensor assembly, a numerical control transverse linear motion unit, a numerical control longitudinal linear motion unit, a machine base and a workpiece supporting disc; the numerical control longitudinal linear motion unit is fixedly arranged on the machine base; the numerical control transverse linear motion unit is arranged on the numerical control longitudinal linear motion unit, and the movement directions of the numerical control longitudinal linear motion unit and the numerical control transverse linear motion unit are mutually perpendicular; the workpiece supporting disc is arranged on the numerical control transverse linear motion unit; the sensor assembly comprises a sensor bracket and two sensors, and the sensors are arranged on the sensor bracket; the sensing points of the two sensors are all positioned on the central axis of the numerical control longitudinal linear motion unit and are arranged front and back.
The workbench is also provided with a numerical control rotary mechanism, the numerical control rotary mechanism is arranged on the numerical control transverse linear motion unit, the workpiece supporting disc is connected with the numerical control rotary mechanism, and the numerical control rotary mechanism drives the workpiece supporting disc to rotate.
The invention is characterized in that: the workpiece supporting disc is a vacuum chuck, an electromagnetic chuck or a pressing plate type workpiece supporting disc; the sensor is a photoelectric sensor, an optical fiber sensor, a laser sensor, an ultrasonic sensor or a proximity switch.
The actuating mechanisms of the numerical control transverse linear motion unit and the numerical control longitudinal linear motion unit are a screw nut mechanism, a gear rack mechanism, a chain transmission mechanism, a belt transmission mechanism, a cam guide rod mechanism, a connecting rod mechanism, an oil cylinder, a linear motor or a linear motion module with a position sensing function.
The invention also comprises a control system, and the sensor, the numerical control rotation mechanism, the numerical control transverse linear motion unit and the numerical control longitudinal linear motion unit are all electrically connected with the control system.
A method for detecting position deviation and alignment of a workpiece by using a sensor, which is characterized in that: by adopting the workbench, the steps are as follows:
setting: x is X 1 Axis, Y 1 The shaft is the center line of the workpiece supporting disc, O 1 The point is the rotation center point of the workpiece supporting disc, X 1 The axis being perpendicular to Y 1 An axis, and X 1 Axes and Y 1 The axes intersect at O 1 A dot; the X axis is the central axis of the numerical control transverse linear motion unit and is connected with X 1 The axes are coincident; the Y axis is used for controlling the central axis of the longitudinal linear motion unit and Y 1 The axes are parallel, and the Y axis and the X axis are perpendicularly intersected at the O point; the distance between the sensing points of the two sensors is L;
1. the detection position deviation and alignment steps of the workpiece with the detected edge being a straight line are as follows:
setting: x is X 2 The axis is O 1 An axis of the point perpendicular to the inspected edge of the workpiece, Y 2 The axis is O 1 An axis of the point parallel to the inspected edge of the workpiece; the workbench is also provided with a numerical control rotary mechanism, the workpiece supporting disc is connected with the numerical control rotary mechanism, and the numerical control rotary mechanism drives the workpiece to supportThe disc rotates;
(1) And (3) a checking process:
loading the workpiece onto a workpiece support tray and triggering inspection: the numerical control longitudinal linear motion unit is fixed, the numerical control transverse linear motion unit moves the workpiece supporting disc and the workpiece on the workpiece supporting disc to a sensor sensing area, a first sensor detects a point on the detected edge of the workpiece, and at the moment, Y is 1 Distance S of axis from Y axis 1 Namely the point is equal to O 1 X axial distance of the point; then the numerical control transverse linear motion unit continues to move the workpiece supporting disc, and the second sensor detects another point on the detected edge of the workpiece, and likewise, Y 1 Distance S of axis from Y axis 2 Namely the point is equal to O 1 X axial distance of the point;
the numerical control transverse linear motion unit continues to move the workpiece supporting disc until O 1 The point coincides with the point O, Y 1 The axis is overlapped with the Y axis, and the inspection operation is finished; according to S 1 And S is equal to 2 Calculating the distance s=s in the X-direction between two detected points 1 -S 2 And then calculating the deflection angle beta of the workpiece as follows:
according to the geometric relationship, the detected edge to O can be obtained 1 The distance K of the points is:
(2) And (3) a deflection angle alignment process:
according to the value of the deflection angle beta, the numerical control rotary mechanism drives the workpiece supporting disc to rotate, and when the rotation stops, the Y axis and the Y axis are respectively arranged at the two ends of the workpiece supporting disc 1 Axis, Y 2 Axis of coincidence, Y 2 O 1 X 2 Coordinate system, Y 1 O 1 X 1 The coordinate system and the YOX coordinate system are overlapped, so that the deflection angle of the workpiece is eliminated; at this time, the detected edge of the workpiece is parallel to the Y axis, and the distance from the detected edge of the workpiece to the Y axis is K, and the detected edge of the workpiece is at Y 2 O 1 X 2 X in a coordinate system 2 The coordinates on the axis, i.e. the X-axis of the detected edge of the workpiece in the YOX coordinate system, are X K ；
(3) And (3) a transverse alignment process:
The deflection angle alignment is completed, and the transverse alignment of the workpiece is started, wherein the transverse alignment is divided into alignment of opposite sides, alignment of a center line or alignment of a center point:
alignment of opposite sides: when the workpiece is at the ideal position of the next station, the detected edge is parallel to the Y axis and the distance between the detected edge and the Y axis is H, and the coordinate value of the detected edge on the X axis is X H The method comprises the steps of carrying out a first treatment on the surface of the The numerical control transverse linear motion unit acts to enable the moving distance of the workpiece to be |x K -x H I, finishing the transverse alignment of the workpiece;
alignment of the center line: let T be the distance from the detected edge to the center line of the workpiece, and let X be the coordinate value of the center line of the workpiece on the X axis T When the ideal position of the workpiece at the next station is set, the distance between the central line and the Y axis in the X axis is P, and the coordinate value of the central line in the X axis is X P The method comprises the steps of carrying out a first treatment on the surface of the The numerical control transverse linear motion unit acts to enable the center line movement distance of the workpiece to be |x P -x T The transverse alignment of the workpiece to the center line is completed;
centering the center point: let T' be the distance from the detected edge to the center point of the workpiece, and let X be the coordinate value of the center point of the workpiece on the X axis T′ When the ideal position of the workpiece at the next station is set, the distance between the center point and the Y axis in the X axis is P', and the coordinate value of the center point in the X axis is X P′ The method comprises the steps of carrying out a first treatment on the surface of the The numerical control transverse linear motion unit acts to enable the movement distance of the center point of the workpiece to be |x P′ -x T′ The transverse centering of the workpiece is completed;
(4) And (3) longitudinal alignment process:
after the transverse alignment is finished, the numerical control longitudinal linear motion unit moves the workpiece along the Y-axis towards the ideal position of the next station, an auxiliary edge is arranged on the workpiece, and after a second sensor detects a point on the auxiliary edge, the numerical control longitudinal linear motion unit moves a fixed distance again, so that the workpiece reaches the ideal position of the next station;
2. the detection position deviation and alignment steps of the workpiece with the detected edge being circular arc or circular are as follows:
(1) And (3) a checking process:
loading the workpiece onto a workpiece support tray and triggering inspection: the numerical control longitudinal linear motion unit is fixed, the numerical control transverse linear motion unit moves the workpiece supporting disc and the workpiece on the workpiece supporting disc to a sensor sensing area, a first sensor detects a point on the detected edge of the workpiece, and at the moment, Y is 1 Distance x of axis from Y axis A Namely the point is equal to O 1 X axial distance of the point; then the numerical control transverse linear motion unit continues to move the workpiece supporting disc, and the second sensor detects another point on the detected edge of the workpiece, and likewise, Y 1 Distance x of axis from Y axis B Namely the point is equal to O 1 X axial distance of the point;
the numerical control transverse linear motion unit continues to move the workpiece supporting disc until O 1 The point coincides with the point O, Y 1 The axes coincide with the Y-axis, the inspection operation is ended, the coordinates of the sensing points of the two sensors on the Y-axis of the YOX coordinate system are (0, L/2) and (0, -L/2), respectively, so that the coordinates of the two detected points are (x) A L/2) and (x) B L/2), the radius of the detected edge is R, then the following set of equations can be obtained:
selecting one of the two solutions of x with small absolute value, using the solution of x to obtain the corresponding value of y, and calculating the coordinate O of the position center of the workpiece in the YOX coordinate system gj (x，y)；
(2) And (3) aligning:
the center coordinates of the workpiece are overlapped with the center coordinates of the workpiece at the ideal position of the next station through the actions of the numerical control transverse linear motion unit and the numerical control longitudinal linear motion unit, so that the workpiece with the detected edge in the shape of a circular arc or a circle can be aligned;
3. the detection position deviation and alignment steps of the workpiece with the detected edge being elliptical are as follows:
set Y 2 The axis is O 1 An axis of the point parallel to the major axis of the ellipse; the workbench is also provided with a numerical control rotation mechanism, the workpiece supporting disc is connected with the numerical control rotation mechanism, and the numerical control rotation mechanism drives the workpiece supporting disc to rotate;
(1) And (3) a checking process:
loading the workpiece onto a workpiece support tray and triggering inspection: the numerical control longitudinal linear motion unit is motionless, and the numerical control transverse linear motion unit moves the workpiece supporting disc and the workpiece on the workpiece supporting disc to the sensor sensing area; the first sensor detects a point on the detected edge of the workpiece, Y 1 Distance x of axis from Y axis A1 Namely the point is equal to O 1 X axial distance of the point; then the numerical control transverse linear motion unit continues to move the workpiece supporting disc, and the second sensor detects a second point on the detected edge of the workpiece, at the moment Y 1 Distance x of axis from Y axis B1 Namely the point is equal to O 1 X axial distance of the point; then the numerical control transverse linear motion unit continues to move the workpiece supporting disc, the first sensor senses the third point on the detected edge of the workpiece, and at the moment, Y 1 Distance x of axis from Y axis A2 Namely the point is equal to O 1 X axial distance of the point; finally, the numerical control transverse linear motion unit continues to move the workpiece supporting disc, and the second sensor senses the fourth point on the detected edge of the workpiece, and at the moment, Y 1 Distance x of axis from Y axis B2 Namely the point is equal to O 1 X axial distance of the point; after the detection of the four points is completed, the transverse linear motion unit moves, when O 1 After the point is overlapped with the point O, Y 1 After the axis is overlapped with the Y axis, the inspection feeding operation is finished; the coordinates of the sensing points of the two sensors on the Y-axis of the YOX coordinate system are (0, L/2) and (0, -L/2), respectively, and then the coordinates of the above four detected points in the YOX coordinate system are respectively: (x) A1 ，L/2)、(x B1 ，-L/2)、(x A2 ，L/2)、(x B2 -L/2); the semi-major axis of the detected edge of the workpiece is a, the semi-minor axis is b, and two foci of the workpiece ellipse are F 1 And F 2 Focal point F at this time 1 Is (x) 1 ，y 1 ) Focus F 2 Is (x) 2 ，y 2 ) The following system of equations can then be obtained:
obtaining F 1 And F 2 After the coordinates of (2), the included angle beta between the ellipse major axis and the Y axis is obtained, the angle is the deflection angle of the ellipse major axis, and the focus F is obtained 1 Distance R to O point:
(2) And (3) a deflection angle alignment process:
according to the value of the deflection angle beta, the numerical control rotary mechanism drives the workpiece supporting disc to rotate, and the Y axis are arranged on the workpiece supporting disc 1 Axis, Y 2 The axes coincide, the elliptic long axis is parallel to the Y axis, and the deflection angle of the elliptic long axis is eliminated;
(3) And (3) a transverse and longitudinal alignment process:
calculating the distance H from the elliptical long axis of the workpiece to the Y axis after deflection angle alignment and the elliptical focus F 1 ' distance M to O Point:
the transverse moving distance of the numerical control transverse linear motion unit is |H| so that the X-axis coordinate of two focuses of the workpiece in a YOX coordinate system is 0, and the transverse position deviation of the workpiece is aligned;
when the workpiece is at the ideal position of the next station, the elliptical focus F of the workpiece is set 1 The distance from the X axis is U, the longitudinal moving distance of the numerical control longitudinal linear motion unit is |U-M|, so that two focuses of the workpiece are overlapped with the focuses of ideal positions, and the longitudinal position deviation of the workpiece is aligned.
In the detecting position deviation and alignment step of the workpiece with the linear detected edge, no deflection angle of the workpiece can appear in extreme cases, in this state, two sensors can detect two points on the detected edge of the workpiece at the same time, at the moment, the deflection angle alignment process is skipped, and the transverse alignment process is directly started.
In the detecting position deviation and alignment step of the workpiece with the detected edge being a straight line, the numerical value of the fixed distance travelled by the numerical control longitudinal linear motion unit is set as follows: when the workpiece is at the ideal position of the next station, the distance from the intersection point of the auxiliary edge and the Y axis to the sensing point of the second sensor is a fixed distance value.
In the detecting position deviation and alignment step of the workpiece with the detected edge being a straight line, the numerical value of the fixed distance travelled by the numerical control longitudinal linear motion unit is set as follows: and setting the distance between the sensing point of the second sensor and the central line of the workpiece at the ideal position of the next station as C, setting the distance between the auxiliary edge and the central line of the workpiece as V, and setting the fixed distance value as |C-V|.
In the step of detecting position deviation and aligning of the workpiece with the arc-shaped or circular detected edge, the action steps of the numerical control transverse linear motion unit and the numerical control longitudinal linear motion unit in the aligning process are as follows: the transverse moving distance of the numerical control transverse linear motion unit is |x| so that the circle center O of the workpiece is achieved gj The X coordinate in the YOX coordinate system is 0, and the transverse position deviation of the workpiece is aligned; the longitudinal moving distance of the numerical control longitudinal linear motion unit is |W-y| so that the circle center O of the workpiece is achieved gj The Y coordinate in the YOX coordinate system is W, and the longitudinal position deviation of the workpiece is aligned.
Compared with the prior art, the invention has the following advantages and effects: the sensor is used for detecting the position deviation of the workpiece, so that the recognition system and the control system are greatly simplified, the workpiece positioning device is applicable to workpieces with various shapes such as triangles, quadrilaterals, polygons, circular arcs or circular and oval shapes, and is especially applicable to occasions such as workpieces made of flexible materials, workpieces made of thin sheets and the like, in which the workpieces are difficult to accurately position in a mechanical limiting mode such as a clamp, a guide and a rigid stop block; and for large-scale work piece, rectangular shape work piece, utilize the workstation of sensor detection work piece position deviation and alignment, also have certain advantage, utilize conventional numerical control motion unit to accomplish the censoring and the alignment of work piece, complete machine simple structure, the operation is reliable, and the rate of accuracy is high, has reduced equipment cost by a wide margin, has improved alignment efficiency.
Drawings
FIG. 1a is a schematic view of a workbench with a numerical control rotary mechanism according to an embodiment of the invention.
Fig. 1b is a schematic side view of the structure of fig. 1 a.
FIG. 1c is a schematic view of a table without a numerical control swing mechanism according to an embodiment of the present invention.
Fig. 1d is a schematic side view of the structure of fig. 1 c.
Fig. 2a is a schematic diagram of a planar coordinate system of a table and a workpiece loading state according to an embodiment of the present invention, in which an upper portion of a workpiece is offset.
Fig. 2b is a schematic diagram of a planar coordinate system of a workbench and a workpiece loading state of a workpiece according to an embodiment of the invention, wherein the lower part of the workpiece is offset.
Fig. 3a is a schematic diagram of alignment of a workpiece with a straight detected edge according to an embodiment of the present invention, in which a point on the detected edge of the workpiece is detected at the detection point of the first sensor.
Fig. 3b is a second alignment schematic diagram of the workpiece with a straight detected edge according to the embodiment of the present invention, in which a point on the detected edge of the workpiece is detected at the detection point of the second sensor.
Fig. 3c is a third alignment schematic diagram of the workpiece with a straight detected edge according to the embodiment of the present invention, in which the inspection operation is finished.
FIG. 3d is a schematic diagram of the alignment of a workpiece with a straight edge to be inspected according to an embodiment of the present invention, wherein the deflection angle of the workpiece has been eliminated.
Fig. 3e is a schematic diagram of alignment of a workpiece with a straight detected edge according to an embodiment of the present invention, in which the lateral alignment of the workpiece is completed.
Fig. 3f is a schematic diagram of alignment of a workpiece with a straight detected edge according to an embodiment of the present invention, in which adjacent edges of the detected edge of the workpiece are detected at a detection point of a second sensor in the longitudinal alignment.
FIG. 4a is a graph showing the alignment of the workpiece on opposite sides and the alignment of the center line according to the embodiment of the invention.
FIG. 4b is a schematic illustration of the geometry of a workpiece aligned laterally with respect to the center line in accordance with an embodiment of the present invention.
FIG. 4c is a schematic illustration of the geometry of a workpiece aligned longitudinally with respect to the center line in accordance with an embodiment of the present invention.
Fig. 5a is a schematic diagram of alignment of a workpiece with a circular arc or a circular arc edge according to an embodiment of the present invention, in which the table is in an initial position.
Fig. 5b is a second alignment schematic diagram of the present invention for a workpiece with a circular arc or a circular edge, where a point on the detected edge of the workpiece is detected at the detection point of the first sensor.
Fig. 5c is a third alignment schematic diagram of the present invention for a workpiece with a circular arc or a circular detected edge, where a point on the detected edge of the workpiece is detected at the detection point of the second sensor.
Fig. 5d is a schematic diagram of alignment of a workpiece with a circular arc or a circular arc edge, in which the inspection operation is completed.
Fig. 6a is a schematic diagram of alignment of a workpiece with an oval edge to be inspected according to an embodiment of the present invention, in which the table is in an initial position and the upper portion of the workpiece is offset.
Fig. 6b is a second alignment schematic diagram of the present invention for a workpiece with an oval detected edge, where a point on the detected edge of the workpiece is detected at the detection point of the first sensor.
Fig. 6c is a third alignment schematic diagram of the present invention for a workpiece with an oval detected edge, where a point on the detected edge of the workpiece is detected at the detection point of the second sensor.
Fig. 6d is a schematic diagram of alignment of a workpiece with an oval detected edge according to an embodiment of the invention, in which another point on the detected edge of the workpiece is detected at the detection point of the first sensor.
Fig. 6e is a schematic diagram of alignment of a workpiece with an oval detected edge according to the embodiment of the invention, in which another point on the detected edge of the workpiece is detected at the detection point of the second sensor.
Fig. 6f is a schematic diagram of alignment of a workpiece with an oval detected edge according to the embodiment of the present invention, in which the inspection operation is completed.
FIG. 6g is a schematic diagram of the alignment of a workpiece with an oval edge to be inspected according to an embodiment of the present invention, wherein the deflection angle of the workpiece has been eliminated.
Fig. 6h is a schematic diagram eight of alignment of a workpiece with an oval edge to be inspected according to an embodiment of the present invention, wherein the lower portion of the workpiece is offset.
In the above figures, the dashed line box G on the upper part of the numerical control longitudinal linear motion unit is the ideal position of the workpiece at the next station.
Detailed Description
The present invention will be described in further detail by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and not limited to the following examples.
The workbench for detecting the position deviation and the alignment of the workpiece 6 by using the sensor comprises a sensor assembly 1, a numerical control transverse linear motion unit 3, a numerical control longitudinal linear motion unit 4, a control system, a machine base 5, a workpiece supporting disc 7, a numerical control transverse linear motion unit bracket 8 and a numerical control longitudinal linear motion unit bracket 9
The numerical control longitudinal linear motion unit 4 is fixedly arranged on the machine base 5 through a numerical control longitudinal linear motion unit bracket 9.
The numerical control transverse linear motion unit 3 is arranged on the numerical control longitudinal linear motion unit 4 through a numerical control transverse linear motion unit bracket 8 and moves linearly along with the numerical control longitudinal linear motion unit 4. The movement of the numerical control longitudinal linear movement unit 4 is realized by a conventional linear movement mechanism with a position sensing function, and the numerical control transverse linear movement unit 3 is dragged to perform linear movement. The movement directions of the numerical control longitudinal linear movement unit 4 and the numerical control transverse linear movement unit 3 are mutually perpendicular.
The workpiece supporting disc 7 is arranged on the numerical control transverse linear motion unit 3 and moves linearly along with the numerical control transverse linear motion unit 3. The workpiece 6 is fixedly placed on the workpiece supporting disc 7, and in order to avoid the relative movement between the workpiece 6 and the workpiece supporting disc 7, the workpiece supporting disc 7 can be a vacuum chuck or an electromagnetic chuck, or can also adopt a pressing plate or other forms to fix the workpiece 6.
The sensor assembly 1 includes a sensor bracket 11 and two sensors 12, the two sensors 12 being a first sensor 121 and a second sensor 122, the first sensor 121 and the second sensor 122 being mounted on the sensor bracket 11. The mutual position relationship between the first sensor 121 and the second sensor 122 is fixed, and the sensing points of the first sensor 121 and the second sensor 122 are all located on the central axis of the longitudinal linear motion unit 4 and are arranged front and back. The sensor 12 is a photoelectric sensor, a fiber optic sensor, a laser sensor, an ultrasonic sensor, or a proximity switch.
The linear motion of the numerical control transverse linear motion unit 3 and the numerical control longitudinal linear motion unit 4 is realized by a conventional linear motion mechanism with a position sensing function, so that an executing mechanism of the numerical control transverse linear motion unit 3 and the numerical control longitudinal linear motion unit 4 can be a screw-nut mechanism, a gear-rack mechanism, a chain transmission mechanism, a belt transmission mechanism, a cam guide rod mechanism, a connecting rod mechanism, an oil cylinder, a linear motor or a linear motion module with the position sensing function.
When the workbench is used for circular and arc-shaped workpieces 6, the workpiece supporting disc 7 is directly installed and fixed on the numerical control transverse linear motion unit 3 and moves linearly along with the numerical control transverse linear motion unit 3.
When the workbench is used for a non-circular and non-circular arc-shaped workpiece 6, the workbench is further provided with a numerical control rotary mechanism 2, and a workpiece supporting disc 7 is arranged on the numerical control transverse linear motion unit 3 through the numerical control rotary mechanism 2. The numerical control swing mechanism 2 includes a motor 21 and a motor bracket 22. The motor support 22 is arranged on the numerical control transverse linear motion unit 3, and the numerical control transverse linear motion unit 3 drives the numerical control rotary mechanism 2 to do linear motion. The motor 21 is mounted vertically upward on a motor bracket 22. The workpiece support disc 7 is mounted on a motor output shaft of the motor 21, and the motor output shaft of the motor 21 drives the workpiece support disc 7 to rotate. The motor 21 is a brake motor with rotary encoder, a stepping motor or a servo motor.
The sensor 12, the numerical control rotary mechanism 2, the numerical control transverse linear motion unit 3 and the numerical control longitudinal linear motion unit 4 are all electrically connected with a control system. The control system is an industrial personal computer or a PLC.
A method for detecting the position deviation and alignment of a workpiece 6 by using a sensor comprises the following steps:
Setting: x is X 1 Axis, Y 1 The axis being the centre line of the work-piece support disc 7, O 1 The point is the rotation center point of the workpiece supporting disc 7, X 1 The axis being perpendicular to Y 1 An axis, and X 1 Axes and Y 1 The axes intersect at O 1 A dot; the X axis is used for controlling the central axis of the transverse linear motion unit 3 and the X 1 The axes are coincident; the Y axis is used for controlling the central axis of the longitudinal linear motion unit 4 and Y 1 The axes are parallel, and the Y axis and the X axis are perpendicularly intersected at the O point; the point A is a sensing point of the first sensor 121, the point B is a sensing point of the second sensor 122, the point A and the point B are both on the Y axis, the distance between the two points A, B is L, and the distance between the point A and the point O is equal to the distance between the point B and the point O in an initial state (namely a loading state); the detected edge is set as a numerical control transverse linear motion sheet in the process of inspectionThe edge of the workpiece 6 that was first detected when the element 3 was moved.
1. The detection position deviation and alignment steps of the workpiece 6 whose detected side is a straight line are as follows:
(1) Setting: x is X 2 The axis is O 1 The vertical foot of the axis of the point vertical to the detected edge of the workpiece is f; y is Y 2 The axis is O 1 An axis of the point parallel to the inspected edge of the workpiece; a. b, c and d are four vertexes of the quadrangular workpiece 6, ab is a detected edge, and the detected edge and X 1 The intersection of the axes is e.
(2) And (3) aligning:
After the workpiece 6 is loaded, there are three dimensional deviations: work pieces 6 and Y 1 O 1 X 1 Deflection angle beta of the coordinate system, i.e. Y 2 And Y is equal to 1 The clamped acute angle, the position deviation of the workpiece 6 in the X-axis direction and the position deviation of the workpiece 6 in the Y-axis direction are eliminated, the alignment process is a process for eliminating the deviation of the workpiece 6 in three dimensions, and the alignment action comprises the following steps:
(21) And (3) a checking process:
fig. 2a shows the initial position of the table, in which the workpiece 6 is mounted on the workpiece support disk 7 and fixed, and then the inspection: the nc longitudinal linear motion unit 4 is stationary, and the nc transverse linear motion unit 3 moves in the opposite direction to the X-axis (leftward in the drawing), so that the workpiece 6 in the workpiece support tray 7 is moved to the sensor sensing area, and a point a 'on the detected edge of the workpiece is detected at a point a' of the first sensor 121 (see fig. 3 a), at this time Y 1 Distance S of axis from Y axis 1 Namely the A' point and O on the detected edge 1 X axial distance of the point; thereafter, the NC-linear motion unit 3 continues to move the work support tray 7, and another point B' (see FIG. 3B) on the detected edge of the work is detected at the point B of the second sensor 122, and likewise, at this time Y 1 Distance S of axis from Y axis 2 Namely B' point and O on the detected edge of the workpiece 1 X axial distance of the point.
Initial position Y of workpiece 6 during loading 1 Distance of axis from Y-axis (i.e. O-point and O 1 The distance of the point) is determined, so that the control system can determine, based on the detection of a second point (point B' in this case) on the detected edge of the workpiece, O 1 The displacement value of the point judges the O point and the O 1 Positional relationship of points (whether O point is on left or O 1 Point on left), the numerical control transverse linear motion unit 3 continues to move the workpiece supporting disc 7 according to the judgment result until O 1 The point coincides with the point O, Y 1 The axis coincides with the Y axis and the inspection operation is ended (see fig. 3 c). According to S 1 And S is equal to 2 The distance s=s in the X-direction between the a 'point and the B' point can be calculated 1 -S 2 Since the distance L between points a and B is known and fixed, the control system can then calculate the deflection angle β of the workpiece 6 as:
according to the geometric relationship, the detected edge to O can be obtained 1 The distance K of the points is:
after the K value is determined, the detected edge of the workpiece is at Y 2 O 1 X 2 X in a coordinate system 2 The coordinates on the axis are then determined.
The above-mentioned inspection process is a case where the deflection direction of the workpiece 6 is as shown in fig. 2a, and when the case where the deflection direction of the workpiece 6 is as shown in fig. 2B occurs, a point B 'on the ab side is detected at the point B in the sensor No. two 122, and then another point a' on the ab side of the workpiece 6 is detected at the point a of the sensor No. 121, in which case the deflection angle β and the detected side are detected as O 1 The calculation principle of the distance K between points is the same, and the control system can determine the direction of the angular deviation of the workpiece 6 only by detecting the sequence of the workpiece 6 according to the first sensor 121 and the second sensor 122, namely: when the sensor 121 detects a point on the ab side, the deflection angle is found, and the numerical control rotary mechanism 2 rotates clockwise to eliminate the deflection angle beta of the workpiece 6; and the second sensor 122 detects a point on the ab side, when the deflection angle is found, the numerical control rotary mechanism rotates anticlockwise to eliminate the deflection angle beta of the workpiece 6.
(22) And (3) a deflection angle alignment process:
the control system sends the rotation direction and the rotation angle value, namely the value of the deflection angle beta, to the numerical control rotation mechanism 2 according to the detection and calculation results, the motor of the numerical control rotation mechanism 2 rotates according to instructions, and when the rotation is stopped, the Y axis and the Y axis are respectively arranged on the Y axis and the Y axis 1 Axis, Y 2 Axis of coincidence, Y 2 O 1 X 2 Coordinate system, Y 1 O 1 X 1 The three coordinate systems coincide with each other, the deflection angle of the workpiece 6 is eliminated (see fig. 3 d), the detected edge of the workpiece is parallel to the Y-axis and the distance to the Y-axis is K, and the detected edge of the workpiece is at Y 2 O 1 X 2 X in a coordinate system 2 The coordinates on the axis, i.e. the X-axis of the detected edge of the workpiece in the YOX coordinate system, are X K 。
In the extreme case, the workpiece 6 will have no deflection angle, in this state, the two sensors 12 will detect 2 points on the detected edge of the workpiece at the same time and send a signal at the same time, and the control system skips the deflection angle alignment process and directly starts the transverse alignment process.
(23) And (3) a transverse alignment process:
the deflection angle alignment is completed, and the workbench automatically starts the transverse alignment of the workpiece 6, and the transverse alignment can be divided into alignment of opposite sides, alignment of a center line or alignment of a center point:
alignment of opposite sides: after alignment, the distance from the detected side ab to the Y axis in the X axis direction is the same as the distance from the ab side to the Y axis in the X axis direction when the workpiece 6 is at the ideal position, and the distance is H. When the workpiece 6 is at the ideal position of the next station, the detected edge is parallel to the Y axis and the distance from the detected edge to the Y axis is H, and the coordinate value of the detected edge on the X axis is X H . The numerical control transverse linear motion unit 3 acts to enable the moving distance of the workpiece 6 to be |x K -x H I, completing the lateral alignment of the workpiece 6 (see fig. 3 e); in extreme cases x K And x H And if the numerical control transverse linear motion unit 3 is the same, the transverse alignment of the workpiece 6 is not performed any more.
Alignment of the center line: depending on the subsequent processing of the workpiece 6, it is also often necessary to realize centering of the workpiece 6 After alignment, i.e. alignment of workpieces 6 with different specifications, the center line E of the workpiece 6 and the ideal center line E 'of the workpiece 6 are on the same straight line, fig. 4a shows the comparison between the alignment of opposite edges and the alignment of the center line, F is the position of the detected edge when the workpiece 6 is in the ideal position, and F' is the position of the center line when the workpiece 6 is in the ideal position. In FIG. 4b, the K value and x are as follows K It has been found that, for workpieces 6 of different specifications, the distance T from the detected edge ab to the center line of the workpiece 6 is known (workpiece 6 specifications differ, T values differ), and that the center line of the workpiece 6 is located to the right of the detected edge of the workpiece, as a result of the inspection process of the workpiece 6, the coordinate value X of the center line on the X-axis T Then determining; when the workpiece 6 is at the ideal position of the next station, the distance from the center line to the Y axis in the X axis is P, and the coordinate value in the X axis is X P The numerical control transverse linear motion unit 3 acts to enable the center line movement distance of the workpiece 6 to be |x P -x T I, the alignment of the transverse alignment center line of the workpiece 6 is completed; in extreme cases x T And x P And if the numerical control transverse linear motion units are the same, the transverse alignment of the workpiece 6 is not performed any more.
Centering the center point: the method for aligning the center point of the workpiece 6 is similar to the method for aligning the center line of the workpiece 6: from the above process, the K value and x K It has been found that, for workpieces 6 of different specifications, the distance T 'of the detected edge ab from the center point of the workpiece 6 is known (workpiece 6 specifications differ, T' value differs), and that the center point of the workpiece 6 is located to the right of the detected edge of the workpiece by the inspection process of the workpiece 6, so that the coordinate value X of the center point on the X-axis T′ Then determining; when the ideal position of the workpiece 6 at the next station is set, the distance between the center point and the Y axis in the X axis is P', and the coordinate value of the workpiece on the X axis is X P′ The numerical control transverse linear motion unit 3 acts to enable the center point movement distance of the workpiece 6 to be |x P′ -x T′ I, finishing the alignment of the transverse centering point of the workpiece 6; in extreme cases x T′ And x P′ And if the numerical control transverse linear motion units are the same, the transverse alignment of the workpiece 6 is not performed any more.
(24) And (3) longitudinal alignment process:
after the transverse alignment process is completed, starting longitudinal alignment and conveying the workpiece 6 to the next station: the servo motor of the numerical control longitudinal linear motion unit 4 is started to enable the workpiece 6 to move forward to the Y axis (upwards in the figure), the auxiliary edge is set to be the edge which is detected firstly when the numerical control longitudinal linear motion unit 4 moves in the longitudinal alignment process, in the embodiment, the auxiliary edge is set to be the adjacent edge bc of the detected edge ab, when a point on the adjacent edge bc of the workpiece 6 is detected at the point B of the second sensor 122, the triggering control system starts the rotation angle counting of the servo motor of the numerical control longitudinal linear motion unit 4, when the counting value is equal to the rotation angle set value of the servo motor, the servo motor of the numerical control longitudinal linear motion unit 4 stops, the workpiece 6 is conveyed to the lower workpiece position, the longitudinal position of the workpiece 6 is aligned at the same time, and the process is equivalent to that after the point B of the second sensor 122 detects the adjacent edge bc of the workpiece 6, the numerical control longitudinal linear motion unit 4 walks a fixed distance D, and the workpiece 6 reaches the ideal position of the next station (see fig. 3 f).
One of the fixed distances D is set in the following manner: when the workpiece 6 is at the ideal position of the next station, the distance from the intersection point of the adjacent side bc and the Y axis to the point B is as follows: each workpiece 6 to be sent to the next station has the same distance from the bc edge to the B point. The longitudinal alignment process is combined with the workpiece conveying action process, so that the process time is saved.
If the workpiece 6 is in a shape with a center line or a symmetrical center point, the workpiece 6 can be aligned with the center line and the center point in the above manner, and the alignment travel of the workpiece 6 with different specifications is set differently, and the corresponding setting can be performed in the program in a manner similar to the alignment of the workpiece 6 with the transverse center line: when the numerically controlled longitudinal linear motion unit 4 moves upward in the figure, after a point on the adjacent side bc of the workpiece 6 is detected at the point B of the second sensor 122, the distance C from the point B of the second sensor 122 to the ideal center line of the workpiece 6 is known, and the distance V from the side bc of the workpiece to the center line of the workpiece 6 is also known (different specifications of the workpiece 6 and V values are different), so that the numerically controlled longitudinal linear motion unit 4 walks by a fixed distance d= |c-v| to complete the longitudinal alignment of the workpiece 6 and simultaneously send the workpiece 6 to the next station.
2. The step of detecting the position deviation and aligning of the workpiece 6 with the detected edge being circular arc or circular is as follows:
(1) And (3) a checking process:
fig. 5a shows the initial position of the table, in which the workpiece 6 is circular, and in which the workpiece 6 is mounted on the workpiece support disk 7 and fixed, and then the inspection: the nc longitudinal linear motion unit 4 is stationary, and the nc transverse linear motion unit 3 moves in the opposite direction to the X-axis (leftward in the drawing) to move the workpiece support tray 7 and the workpiece 6 thereon to the sensor sensing area, and detects a point a' (see fig. 5 b) on the detected edge of the workpiece at a point a of the sensor 121, at which point Y 1 Distance x of axis from Y axis A Namely the point A' and O 1 X axial distance of the point; thereafter, the NC-linear motion unit 3 continues to move the work support tray 7, and another point B' (see FIG. 5 c) on the detected edge of the work is detected at the point B of the second sensor 122, and likewise, at this time Y 1 Distance x of axis from Y axis B Namely B' point and O on the detected edge of the workpiece 1 X axial distance of the point.
Initial position Y of workpiece 6 during loading 1 Distance of axis from Y-axis (i.e. O-point and O 1 The distance of the point) is determined, so that the control system can determine the distance of the point based on O when the second point on the detected edge of the workpiece is detected 1 The displacement value of the point judges the O point and the O 1 Positional relationship of points (whether O point is on left or O 1 Point on left), the numerical control transverse linear motion unit 3 continues to move the workpiece supporting disc 7 according to the judgment result until O 1 The point coincides with the point O, Y 1 The axis coincides with the Y-axis, the inspection operation is ended, the coordinates of the A ' and B ' points on the X-axis of the YOX coordinate system are determined, and the coordinates of the A and B points on the Y-axis of the YOX coordinate system are known as (0, L/2) and (0, -L/2), respectively, so that the A ' point coordinates are (X A L/2), the coordinates of the B' point are (x) B L/2), while the radius R of the arc of the workpiece 6 is also known, the following set of equations is then available:
the right sides of two points A 'and B' with the circle centers on the circular arc can be known by the inspection process, namely: selecting one of the two solutions of x with smaller absolute value, and using the solution of x to obtain the corresponding value of y, so that the control system calculates the coordinate O of the position center of the workpiece 6 in the YOX coordinate system gj (x，y)。
(2) And (3) aligning:
FIG. 5d, coordinates of the ideal position of the workpiece 6 centered on the YOX coordinate system are (0, W), and the actual center position of the workpiece 6 calculated from the control system is at the coordinates O of the YOX coordinate system gj (x, y) by the actions of the numerical control transverse linear motion unit 3 and the numerical control longitudinal linear motion unit 4, the circle center of the workpiece 6 is sent to an ideal center position (0, W), namely: the center coordinates of the workpiece 6 are overlapped with the coordinates of the ideal position of the workpiece 6, so that the workpiece 6 with the detected edge in the shape of a circular arc or a circle can be aligned, and the specific steps are as follows:
The transverse moving distance of the numerical control transverse linear motion unit 3 is |x| so that the circle center O of the workpiece 6 is achieved gj The X coordinate in the YOX coordinate system is 0 (consistent with the abscissa of the ideal position of the circle center), and the transverse position deviation of the workpiece 6 is aligned;
the longitudinal moving distance of the numerical control longitudinal linear motion unit 4 is |W-y| so that the circle center O of the workpiece 6 is achieved gj The Y-coordinate in YOX coordinate system is W (the ordinate of ideal position of circle center is identical), the longitudinal position deviation of workpiece 6 is aligned, and workpiece 6 is delivered to next station.
The work table for the circular arc-shaped and circular workpieces 6 can be simply used without the numerical control rotary mechanism 2 as known from the process of inspecting and aligning the circular arc-shaped and circular workpieces 6.
3. The detection position deviation and alignment steps of the workpiece 6 with the detected edge being elliptical are as follows:
(1) And (3) a checking process:
FIG. 6a shows the initial position of the table, the workpiece 6 is elliptical, and Y is set 2 The axis is O 1 An axis of the point parallel to the major axis of the ellipse; in this position the workpiece 6 is mounted on the workpiece support disk 7 and securedAnd (3) determining, and triggering the censoring:
the nc longitudinal linear motion unit 4 is stationary, and the nc transverse linear motion unit 3 moves in the opposite direction to the X-axis (leftward in the drawing) to move the workpiece support tray 7 and the workpiece 6 thereon to the sensor sensing area, and detects a point A1 (see fig. 6 b) on the detected edge of the workpiece at a point a of the sensor 121, at which point Y 1 Distance x of axis from Y axis A1 Namely the A1 point and O on the detected edge of the workpiece 1 X axial distance of the point; thereafter, the NC-linear motion unit 3 continues to move the work support tray 7, and a second point B1 (see FIG. 6 c) on the detected side of the work is detected at the point B of the second sensor 122, and likewise, at this time Y 1 Distance x of axis from Y axis B1 Namely B1 point and O on the detected edge of the workpiece 1 X axial distance of the point; thereafter, the NC-linear motion unit 3 continues to move the workpiece support tray 7, and senses a third point A2 (see FIG. 6 d) on the detected edge of the workpiece at the point A of the first sensor 121, and likewise, at this time Y 1 Distance x of axis from Y axis A2 Namely B' point and O on the detected edge of the workpiece 1 X axial distance of the point; finally, the numerically controlled transverse linear motion unit 3 continues to move the workpiece support tray 7, and senses the fourth point B2 on the detected edge of the workpiece at the point B of the second sensor 122, and likewise, at this time Y 1 Distance x of axis from Y axis B2 Namely B2 point and O on the detected edge of the workpiece 1 X axial distance of the point; after the detection of the 4 points A1, A2, B1 and B2 is completed, the transverse linear motion unit 3 moves, when O 1 After the point is overlapped with the point O, the servo motor of the transverse linear motion unit 3 stops, Y 1 The axis coincides with the Y axis, FIG. 6f shows the state at the end of the inspection operation, where the coordinates of the X axis in the YOX coordinate system are determined for the point A1, the point B1, the point A2, and the point B, and the coordinates of the point A and the point B in the Y axis in the YOX coordinate system are known to be (0, L/2), (0, -L/2), respectively, so that the point A1 is the (X A1 L/2), the coordinates of the B1 point are (x) B1 -L/2), the coordinates of the A2 point being (x) A2 L/2), the coordinates of the B2 point are (x) B2 -L/2); while the semi-major axis a, semi-minor axis b and focal length of the detected edge of the workpiece are known, a focal point F is provided 1 Is (x) 1 ，y 1 )，Focus F 2 Is (x) 2 ，y 2 ) The following system of equations can then be obtained:
obtaining F 1 And F 2 After the coordinates of (2), the equation of the ellipse major axis in the YOX coordinate system can be obtained, and the included angle beta between the ellipse major axis and the Y axis, which is the deflection angle of the ellipse major axis, can be obtained, and the focus F can be obtained 1 Distance R to O point:
the control system sends the values of the rotation direction and the rotation angle beta to a servo controller of the numerical control rotation mechanism 2, and a motor of the numerical control rotation mechanism 2 rotates according to instructions, and the motor is provided with a Y axis and a Y axis 1 Axis, Y 2 The axes coincide, the major axis of the ellipse is parallel to the Y axis, the deflection angle of the major axis of the ellipse is eliminated, and the transverse position deviation and the longitudinal position deviation of the ellipse are calculated. As shown in fig. 6g, the two-dot chain ellipse in the figure is the position of the workpiece 6 before the deflection angle alignment, the solid ellipse is the position of the workpiece 6 after the deflection angle alignment, F 1 ' is an elliptical focus F 1 From the geometrical relationship of FIG. 6g, the new position at the completion of the yaw angle alignment can be obtained from the major axis of the ellipse to Y Distance of axis H and elliptical focus F 1 Distance M to O point:
the transverse position deviation and the longitudinal position deviation of the ellipse are completely determined, and then the transverse position deviation and the longitudinal position deviation of the ellipse are aligned in a similar way to the alignment of the circular (circular arc) workpiece 6, namely, the workpiece 6 focus is sent to an ideal position through the numerical control transverse linear motion unit 3 and the numerical control longitudinal linear motion unit 4, and the specific steps are as follows:
the transverse moving distance of the numerical control transverse linear motion unit 3 is |H| so that the coordinates of two focuses of the workpiece 6 in a YOX coordinate system are 0, and the transverse position deviation of the workpiece 6 is aligned;
setting the elliptical focus F when the workpiece 6 is at the ideal position of the next station 1 The distance from the X axis is U, the longitudinal movement distance of the numerical control longitudinal linear movement unit 4 is |U-M|, so that two focuses of the workpiece 6 are overlapped with the ideal position focuses, the longitudinal position deviation of the workpiece 6 is aligned, and the workpiece 6 is conveyed to the next station.
Similarly, when the deflection direction of the workpiece 6 is as shown in fig. 6h, similarly to the case of the workpiece 6 with the detected edge being a straight line, the point B of the second sensor 122 detects a point B 'on the elliptical outline of the workpiece 6 first, and then the point a of the first sensor 121 detects another point a' on the elliptical outline of the workpiece 6, in this case, the calculation principle of each deflection value of the ellipse of the workpiece 6 is the same as that in the case that the point a of the first sensor 121 detects a point on the elliptical outline of the workpiece 6 first, and the control system only needs to determine the direction of the angular deviation of the major axis of the ellipse of the workpiece 6 according to the sequence in which the two sensors detect the workpiece 6, namely: when the first sensor 121 detects a point on the oval outline, the deflection angle is found, the numerical control rotary mechanism 2 rotates clockwise to eliminate the deflection angle of the workpiece 6, and when the second sensor 122 detects a point on the oval outline, the deflection angle is found, and the numerical control rotary mechanism rotates anticlockwise to eliminate the deflection angle of the workpiece 6.
In addition, it should be noted that the specific embodiments described in the present specification may vary from part to part, from name to name, etc., and the above description in the present specification is merely illustrative of the structure of the present invention. All equivalent or simple changes of the structure, characteristics and principle according to the inventive concept are included in the protection scope of the present patent. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions in a similar manner without departing from the scope of the invention as defined in the accompanying claims.

Claims (5)

1. A method for detecting position deviation and alignment of a workpiece by using a sensor, which is characterized in that: a workbench is adopted, and comprises a sensor assembly, a numerical control transverse linear motion unit, a numerical control longitudinal linear motion unit, a machine base and a workpiece supporting disc; the numerical control longitudinal linear motion unit is fixedly arranged on the machine base; the numerical control transverse linear motion unit is arranged on the numerical control longitudinal linear motion unit, and the movement directions of the numerical control longitudinal linear motion unit and the numerical control transverse linear motion unit are mutually perpendicular; the workpiece supporting disc is arranged on the numerical control transverse linear motion unit; the sensor assembly comprises a sensor bracket and two sensors, and the sensors are arranged on the sensor bracket; the sensing points of the two sensors are positioned on the central axis of the numerical control longitudinal linear motion unit and are arranged front and back;
The method comprises the following steps:
setting: x is X 1 Axis, Y 1 The shaft is the center line of the workpiece supporting disc, O 1 The point is the rotation center point of the workpiece supporting disc, X 1 The axis being perpendicular to Y 1 An axis, and X 1 Axes and Y 1 The axes intersect at O 1 A dot; the X axis is the central axis of the numerical control transverse linear motion unit and is connected with X 1 The axes are coincident; y-axis numerical control longitudinal directionToward the central axis of the linear motion unit and Y 1 The axes are parallel, and the Y axis and the X axis are perpendicularly intersected at the O point; the distance between the sensing points of the two sensors is L;
1. the detection position deviation and alignment steps of the workpiece with the detected edge being a straight line are as follows:
setting: x is X 2 The axis is O 1 An axis of the point perpendicular to the inspected edge of the workpiece, Y 2 The axis is O 1 An axis of the point parallel to the inspected edge of the workpiece; the workbench is also provided with a numerical control rotary mechanism, the workpiece supporting disc is connected with the numerical control rotary mechanism, and the numerical control rotary mechanism drives the workpiece supporting disc to rotate;
(1) And (3) a checking process:
loading the workpiece onto a workpiece support tray and triggering inspection: the numerical control longitudinal linear motion unit is fixed, the numerical control transverse linear motion unit moves the workpiece supporting disc and the workpiece on the workpiece supporting disc to a sensor sensing area, a first sensor detects a point on the detected edge of the workpiece, and at the moment, Y is 1 Distance S of axis from Y axis 1 Namely the point is equal to O 1 X axial distance of the point; then the numerical control transverse linear motion unit continues to move the workpiece supporting disc, and the second sensor detects another point on the detected edge of the workpiece, and likewise, Y 1 Distance S of axis from Y axis 2 Namely the point is equal to O 1 X axial distance of the point;
the numerical control transverse linear motion unit continues to move the workpiece supporting disc until O 1 The point coincides with the point O, Y 1 The axis is overlapped with the Y axis, and the inspection operation is finished; according to S 1 And S is equal to 2 Calculating the distance s=s in the X-direction between two detected points 1 -S 2 And then calculating the deflection angle beta of the workpiece as follows:
according to the geometric relationship, the detected edge to O can be obtained 1 The distance K of the points is:
(2) And (3) a deflection angle alignment process:
according to the value of the deflection angle beta, the numerical control rotary mechanism drives the workpiece supporting disc to rotate, and when the rotation stops, the Y axis and the Y axis are respectively arranged at the two ends of the workpiece supporting disc 1 Axis, Y 2 Axis of coincidence, Y 2 O 1 X 2 Coordinate system, Y 1 O 1 X 1 The coordinate system and the YOX coordinate system are overlapped, so that the deflection angle of the workpiece is eliminated; at this time, the detected edge of the workpiece is parallel to the Y axis, and the distance from the detected edge of the workpiece to the Y axis is K, and the detected edge of the workpiece is at Y 2 O 1 X 2 X in a coordinate system 2 The coordinates on the axis, i.e. the X-axis of the detected edge of the workpiece in the YOX coordinate system, are X K ；
(3) And (3) a transverse alignment process:
the deflection angle alignment is completed, and the transverse alignment of the workpiece is started, wherein the transverse alignment is divided into alignment of opposite sides, alignment of a center line or alignment of a center point:
alignment of opposite sides: when the workpiece is at the ideal position of the next station, the detected edge is parallel to the Y axis and the distance between the detected edge and the Y axis is H, and the coordinate value of the detected edge on the X axis is X H The method comprises the steps of carrying out a first treatment on the surface of the The numerical control transverse linear motion unit acts to enable the moving distance of the workpiece to be |x K -x H I, finishing the transverse alignment of the workpiece;
alignment of the center line: let T be the distance from the detected edge to the center line of the workpiece, and let X be the coordinate value of the center line of the workpiece on the X axis T When the ideal position of the workpiece at the next station is set, the distance between the central line and the Y axis in the X axis is P, and the coordinate value of the central line in the X axis is X P The method comprises the steps of carrying out a first treatment on the surface of the The numerical control transverse linear motion unit acts to enable the center line movement distance of the workpiece to be |x P -x T The transverse alignment of the workpiece to the center line is completed;
centering the center point: let T' be the distance from the detected edge to the center point of the workpiece, and let X be the coordinate value of the center point of the workpiece on the X axis T′ When the ideal position of the workpiece at the next station is set, the distance between the center point and the Y axis in the X axis is P', and the coordinate value of the center point in the X axis is X P′ The method comprises the steps of carrying out a first treatment on the surface of the Numerical controlThe transverse linear motion unit acts to make the movement distance of the center point of the workpiece be |x P′ -x T′ The transverse centering of the workpiece is completed;
(4) And (3) longitudinal alignment process:
after the transverse alignment is finished, the numerical control longitudinal linear motion unit moves the workpiece along the Y-axis towards the ideal position of the next station, an auxiliary edge is arranged on the workpiece, and after a second sensor detects a point on the auxiliary edge, the numerical control longitudinal linear motion unit moves a fixed distance again, so that the workpiece reaches the ideal position of the next station;
2. the detection position deviation and alignment steps of the workpiece with the detected edge being circular arc or circular are as follows:
(1) And (3) a checking process:
loading the workpiece onto a workpiece support tray and triggering inspection: the numerical control longitudinal linear motion unit is fixed, the numerical control transverse linear motion unit moves the workpiece supporting disc and the workpiece on the workpiece supporting disc to a sensor sensing area, a first sensor detects a point on the detected edge of the workpiece, and at the moment, Y is 1 Distance x of axis from Y axis A Namely the point is equal to O 1 X axial distance of the point; then the numerical control transverse linear motion unit continues to move the workpiece supporting disc, and the second sensor detects another point on the detected edge of the workpiece, and likewise, Y 1 Distance x of axis from Y axis B Namely the point is equal to O 1 X axial distance of the point;
the numerical control transverse linear motion unit continues to move the workpiece supporting disc until O 1 The point coincides with the point O, Y 1 The axes coincide with the Y-axis, the inspection operation is ended, the coordinates of the sensing points of the two sensors on the Y-axis of the YOX coordinate system are (0, L/2) and (0, -L/2), respectively, so that the coordinates of the two detected points are (x) A L/2) and (x) B L/2), the radius of the detected edge is R, then the following set of equations can be obtained:
selecting one of the two solutions of x with small absolute value, using the solution of x to obtain the corresponding value of y, and calculating the coordinate O of the position center of the workpiece in the YOX coordinate system gj (x，y)；
(2) And (3) aligning:
the center coordinates of the workpiece are overlapped with the center coordinates of the workpiece at the ideal position of the next station through the actions of the numerical control transverse linear motion unit and the numerical control longitudinal linear motion unit, so that the workpiece with the detected edge in the shape of a circular arc or a circle can be aligned;
3. the detection position deviation and alignment steps of the workpiece with the detected edge being elliptical are as follows:
set Y 2 The axis is O 1 An axis of the point parallel to the major axis of the ellipse; the workbench is also provided with a numerical control rotation mechanism, the workpiece supporting disc is connected with the numerical control rotation mechanism, and the numerical control rotation mechanism drives the workpiece supporting disc to rotate;
(1) And (3) a checking process:
loading the workpiece onto a workpiece support tray and triggering inspection: the numerical control longitudinal linear motion unit is motionless, and the numerical control transverse linear motion unit moves the workpiece supporting disc and the workpiece on the workpiece supporting disc to the sensor sensing area; the first sensor detects a point on the detected edge of the workpiece, Y 1 Distance x of axis from Y axis A1 Namely the point is equal to O 1 X axial distance of the point; then the numerical control transverse linear motion unit continues to move the workpiece supporting disc, and the second sensor detects a second point on the detected edge of the workpiece, at the moment Y 1 Distance x of axis from Y axis B1 Namely the point is equal to O 1 X axial distance of the point; then the numerical control transverse linear motion unit continues to move the workpiece supporting disc, the first sensor senses the third point on the detected edge of the workpiece, and at the moment, Y 1 Distance x of axis from Y axis A2 Namely the point is equal to O 1 X axial distance of the point; finally, the numerical control transverse linear motion unit continues to move the workpiece supporting disc, and the second sensor senses the fourth point on the detected edge of the workpieceAt this time Y 1 Distance x of axis from Y axis B2 Namely the point is equal to O 1 X axial distance of the point; after the detection of the four points is completed, the transverse linear motion unit moves, when O 1 After the point is overlapped with the point O, Y 1 After the axis is overlapped with the Y axis, the inspection feeding operation is finished; the coordinates of the sensing points of the two sensors on the Y-axis of the YOX coordinate system are (0, L/2) and (0, -L/2), respectively, and then the coordinates of the above four detected points in the YOX coordinate system are respectively: (x) A1 ，L/2)、(x B1 ，-L/2)、(x A2 ，L/2)、(x B2 -L/2); the semi-major axis of the detected edge of the workpiece is a, the semi-minor axis is b, and two foci of the workpiece ellipse are F 1 And F 2 Focal point F at this time 1 Is (x) 1 ，y 1 ) Focus F 2 Is (x) 2 ，y 2 ) The following system of equations can then be obtained:
obtaining F 1 And F 2 After the coordinates of (2), the included angle beta between the ellipse major axis and the Y axis is obtained, the angle is the deflection angle of the ellipse major axis, and the focus F is obtained 1 Distance R to O point:
(2) And (3) a deflection angle alignment process:
according to the value of the deflection angle beta, the numerical control rotary mechanism drives the workpiece supporting disc to rotate, and the Y axis are arranged on the workpiece supporting disc 1 Axis, Y 2 The axes coincide, the elliptic long axis is parallel to the Y axis, and the deflection angle of the elliptic long axis is eliminated;
(3) And (3) a transverse and longitudinal alignment process:
calculating the distance H from the elliptical long axis of the workpiece to the Y axis after deflection angle alignment and the elliptical focus F 1 ' distance M to O Point:
the transverse moving distance of the numerical control transverse linear motion unit is |H| so that the X-axis coordinate of two focuses of the workpiece in a YOX coordinate system is 0, and the transverse position deviation of the workpiece is aligned;
when the workpiece is at the ideal position of the next station, the elliptical focus F of the workpiece is set 1 The distance from the X axis is U, the longitudinal moving distance of the numerical control longitudinal linear motion unit is |U-M|, so that two focuses of the workpiece are overlapped with the focuses of ideal positions, and the longitudinal position deviation of the workpiece is aligned.
2. The method for detecting positional deviation and alignment of a workpiece using a sensor as claimed in claim 1, wherein: in the detecting position deviation and alignment step of the workpiece with the detected edge being a straight line, no deflection angle of the workpiece upper part can appear in extreme cases, in this state, two sensors can detect two points on the detected edge of the workpiece at the same time, at the moment, the deflection angle alignment process is skipped, and the transverse alignment process is directly started.
3. The method for detecting positional deviation and alignment of a workpiece using a sensor as claimed in claim 1, wherein: in the detecting position deviation and alignment step of the workpiece with the detected edge being a straight line, the numerical value of the fixed distance travelled by the numerical control longitudinal linear motion unit is set as follows: when the workpiece is at the ideal position of the next station, the distance from the intersection point of the auxiliary edge and the Y axis to the sensing point of the second sensor is a fixed distance value.
4. The method for detecting positional deviation and alignment of a workpiece using a sensor as claimed in claim 1, wherein: in the detecting position deviation and alignment step of the workpiece with the detected edge being a straight line, the numerical value of the fixed distance travelled by the numerical control longitudinal linear motion unit is set as follows: and setting the distance between the sensing point of the second sensor and the central line of the workpiece at the ideal position of the next station as C, setting the distance between the auxiliary edge and the central line of the workpiece as V, and setting the fixed distance value as |C-V|.
5. The method for detecting positional deviation and alignment of a workpiece using a sensor as claimed in claim 1, wherein: in the steps of detecting position deviation and aligning of a workpiece with a circular arc or a circular detected edge, the numerical control transverse linear motion unit and the numerical control longitudinal linear motion unit in the aligning process have the following action steps: the transverse moving distance of the numerical control transverse linear motion unit is |x| so that the circle center O of the workpiece is achieved gj The X coordinate in the YOX coordinate system is 0, and the transverse position deviation of the workpiece is aligned; the longitudinal moving distance of the numerical control longitudinal linear motion unit is |W-y| so that the circle center O of the workpiece is achieved gj The Y coordinate in the YOX coordinate system is W, and the longitudinal position deviation of the workpiece is aligned.
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